There was an 18 month gap between 2.3 and 2.4, so you'll probably be waiting a while for new features, but I doubt they've been decided on yet. You could try the Python Enhancement Proposals (PEPs) for suggested inclusions:

The core Python guys are still working in Python 2.3.5 as well, although there wont be any new features added to this release it's good news for those still using Python 2.3 as there main Python version .

As for the new features added to Python 2.4 here are a few interesting links.

The Python developers have a system called PEPs - Python Enhancement Proposals. Anyone can propose an enhancement, write it up as a PEP, and submit it for discussion. PEPs that are accepted will then be incorporated into a future release. This lets everyone see what is in the works for the next release.